AIYIMA A07 TPA3255 Amplifier Measurements and Review - LM4562 (and OPA2134) option

[DualTriode]

I have ordered Mean Well RS-100-24 SMPS power supply, 24V/4.5A. The cost is about $30 in a local store.

View attachment 106010
I will measure the A07 output power and spectrum cleanliness with this power supply. I cannot recommend a 48V power supply because of the A07 internal temperature with the 48V PSU, in case I want to get a reasonable life time of the amplifier. Yes the unit like this must be covered in an appropriate case for safety reasons.

Here is the datasheet

Hello,

Any news on the Mean Well power supply?

Thanks DT

 

[jokan]

Very interesting testing and well documented.
May I suggest the OPA1656 as a possible substitute to the tried and tested LM4562?
I run them myself after having ran the LM4562 for years. I have 6 unused, original USA made 4562's their great, but I am now using the OPA1656.

https://www.ti.com/lit/gpn/opa1656
VS
https://www.ti.com/lit/gpn/lm4562

I have had great success with them in various pieces of equipment and have become my go-to op-amp. I still have my discrete Burson, and Sparkos but not the pro grade, I can't fit into any of the equipment I own, but I put the Burson vivid5i, 6Vivid in a drawer where they've been for some time.

It might be worth giving the 1656's a go.

Just a thought. Can't hurt to offer a suggestion. It's up to you to make any and all decisions.

 

[DualTriode]

Hello,

Related question.

Is there a similar bargain Class AB amplifier with a swappable switching power supply?

Thanks DT

 

[xtenz]

Hello,
Do you think this amp can be use with a compression driver BMS 4550 ( 80W AES , 113 db sensitivity, 8 Ohms ) high pass from 1.2Khz to above ? Or it is a bad option and I should go with a litlle AB class amp.
Thanks

 

[pma]

Just found a space to test AIYIMA A07 with OPA2134 opamp. It works with no problems. Noise is almost same as with LM4562 and there are no problems with distortion. Noise of the A07 is mostly defined by high resistance values in its resistor network around the input dual opamp, there is no chance for improvement without re-designing. So there is no need to seek for SOTA newest opamps.

Noise

Distortion - measured into 4 ohm load, with my MeanWell 24V SMPS set to 27V. THD vs. power was measured at 1kHz and 6kHz and measurement BW @40kHz.

 

[pma]

We have now SINAD = 88dB at 5W/4ohm/1kHz and @24kHz BW.

So considering NE5532, LM4562 and OPA2134, OPA2134 gives best measured results in AIYIMA A07. And it is a JFET opamp, which is always preferred by myself in the positions where slightly higher voltage noise of the opamp is negligible, like here. We get lower current noise and better EMI resistence.

 

[Bruce Morgen]

So there is no need to seek for SOTA newest opamps.

...and that confirms my initial surmise: that there is really little or no substantive advantage to the whole "op amp rolling" procedure in the vast majority of cases, this dandy little $50 power amp very much included.

 

[Ralferator]

...and that confirms my initial surmise: that there is really little or no substantive advantage to the whole "op amp rolling" procedure in the vast majority of cases, this dandy little $50 power amp very much included.

I guess leaning an inch forward and listening more concentrated for the differences already makes all the difference. Being a little further from the back wall with the ears, tightens up the bass, which makes the whole sound less muddy and more detailed, tight and whatever. That's just my guess

 

[jokan]

...and that confirms my initial surmise: that there is really little or no substantive advantage to the whole "op amp rolling" procedure in the vast majority of cases, this dandy little $50 power amp very much included.

op-amp rolling in most cases seems to be a little bit more or less like adding a little sprinkle of salt and pepper or taking it away. It really depends on speaker placement and specific equipment combinations more than the op-amp in and of itself in my experience. The best op-amp is no op-amp is my ultimate belief. I particularly don't like devices that have double up on op-amps input and driver. Though I must admit to not being familiar at all with any aiyima amplifiers. Though op-amp rolling is fun to tinker around with, I have an easy 2 dozen op-amps in my collection each of which holds it's rightful place. Today's op-amps are so good to begin with, the difference is indeed subtle at best. There are usually more gains with speaker placement than there are with op-amp rolling. Even a slight Toe change can make a bigger improvement with the same speakers in my experience. Not to take anything away from any readers experience with their equipment and room. Lastly, as long as you enjoy the change that is all that really matters in the end.

Happy listening!

 

[DualTriode]

For this amplifier the Operational Amplifier is not a major contributor. With the resistor values selected in positions around the op-amp the op-amp selection does not make much of a difference.

On the other hand, swapping out the power supply does seem to be important to the amplifier performance.

DT

 

[jokan]

For this amplifier the Operational Amplifier is not a major contributor. With the resistor values selected in positions around the op-amp the op-amp selection does not make much of a difference.

On the other hand, swapping out the power supply does seem to be important to the amplifier performance.

DT

Power supply quality is what defines any amplifier in the end. The type or style of the power supply, the instant current it can supply, and how clean the power is are always the defining characteristics of an amplifier and easily the most expensive part of a high quality amplifier. This hasn't changed for many decades.

 

[hoverdonkey]

I have ordered an A07 and am now looking for a power supply to get me started (it didn't come with one). I have read through this thread and failed to find a clear way forward. Might one of these be okay:

https://www.amazon.co.uk/DSLRKIT-10...child=1&keywords=48v+3a&qid=1625171675&sr=8-5

It seems to be a similar rating to the one used in the original review of the A07 here on ASR (48V 3A), in which amp performed well. I can't see the 32V 5A one for sale here in the UK.

Or one of these perhaps? Mean Well LPV-150-24:

https://www.ebay.co.uk/itm/274690797444?hash=item3ff4d8ef84:g:5OYAAOSwQndgMSje


Any recommendations welcome!

 

[hoverdonkey]

I think I just found my answer on your MW RS-100-24 SMPS test thread, thank you @pma ! I found the LRS version on Amazon UK (only £15, which is pleasing). Hopefully the LRS verison has similar performance to the RS.

I also found this 48V 12.5A unit that I couldn't resist for comparison 'cos it was only £9 (but it's £38 now, so it might have been a misprice).

I really need my A07 to arrive now!

 

[jokan]

I think I just found my answer on your MW RS-100-24 SMPS test thread, thank you @pma ! I found the LRS version on Amazon UK (only £15, which is pleasing). Hopefully the LRS verison has similar performance to the RS.

I also found this 48V 12.5A unit that I couldn't resist for comparison 'cos it was only £9 (but it's £38 now, so it might have been a misprice).

I really need my A07 to arrive now!

let us know about your findings. start things off with the lowest power/amperage PSU. And be nice to your amp by letting it play for a day before you make any judgements. There are lots of passive components inside of your amplifier and they do change over a day of solid listening. Play your music at human talking volumes and not rock concert levels for a day. I recommend this for any brand new amplifier just to be nice to the internal parts. The capacitors, and resistors inside of modern amplifiers still need to be cycled a few times and you'll probably start to hear differences after you turn your amplifier off once or twice. It's just a smart thing to do.

I am following the thread as I am curious to hear about your findings as well as those who own the same amplifier. Subjective opinions are fine and what I actually want to know. I don't need graphs or data. Just your personal opinion!

Cheers!

 

[hoverdonkey]

let us know about your findings. start things off with the lowest power/amperage PSU. And be nice to your amp by letting it play for a day before you make any judgements. There are lots of passive components inside of your amplifier and they do change over a day of solid listening. Play your music at human talking volumes and not rock concert levels for a day. I recommend this for any brand new amplifier just to be nice to the internal parts. The capacitors, and resistors inside of modern amplifiers still need to be cycled a few times and you'll probably start to hear differences after you turn your amplifier off once or twice. It's just a smart thing to do.

I am following the thread as I am curious to hear about your findings as well as those who own the same amplifier. Subjective opinions are fine and what I actually want to know. I don't need graphs or data. Just your personal opinion!

Cheers!

I certainly will report back. It can only be subjective, as the only audio testing equipment that I have are my ears!

Thanks for running-in tips.

 

[abdo123]

THD vs. amplitude at 1kHz and 6kHz / 4ohm, unregulated 50V power supply
View attachment 104323

Please note the strange nonlinear behavior at 6kHz. This is completely in conformance with TI SLAA788A document, Fig.87

@pma what is the amperage of the 50V PSU you're using? I have a 48V 4.3A power supply and i'm trying to figure out what is my peak power.

 

[pma]

@pma what is the amperage of the 50V PSU you're using? I have a 48V 4.3A power supply and i'm trying to figure out what is my peak power.

My unregulated 50V PSU is able to supply 10A current. With 4.3A you would be limited to some 74W/4ohm, higher voltage does not help as you are limited by current, P = R*I^2.

 

[abdo123]

My unregulated 50V PSU is able to supply 10A current. With 4.3A you would be limited to some 74W/4ohm, higher voltage does not help as you are limited by current, P = R*I^2.

and @8Ohm? (that's actually the impedance of my subwoofer).

 

[Deleted member 9685]

It seems paying a few more dollars for LM4562 op amp instead of NE5532 doesn't really make much sense.
LM4562 may be slightly better, but the difference is not audible.

 

[TheWalkman]

It seems paying a few more dollars for LM4562 op amp instead of NE5532 doesn't really make much sense.
LM4562 may be slightly better, but the difference is not audible.

But like many things audio related, it may make no real difference to swap the chips, but it’s so fun to pop the top and roll new op amps. (Similarly, in the motorcycle world, this phonomina is called, “farkling.” In homes, it’s called decorating. In spouses: makeup.)

For a $5 investment, isn’t it worth it to know in your heart that the distortion of your op amp has gone from 0.003 percent to 0.000003%, in a $50 amp, no less? That’s the stuff that keeps us all coming back to ASR!